Chairs or spacers are commonly used in the construction industry for the support and positioning of steel reinforcement members, such as wire mesh, post-tension cables and/or reinforcement bars (“rebar”), a proper distance above a surface. The bars or cables are usually arranged in rows or grids within an area into which concrete is to be poured. They are held loosely in place while concrete is placed around them. In normal
Proper spacing and arrangement of steel reinforcement members in concrete slabs and/or tilt-up panels according to known engineering and architectural specifications impacts the structural strength and integrity of the concrete structure. Such steel reinforcement requires sufficient cover to avoid exposing the steel to the effects of moisture-penetrating corrosion. Once the steel is exposed to the effects of chemical-laden moisture, corrosion starts taking effect.
Known prior art chairs have desirable features which provide the proper support of rebar or post-tension cables safely within a concrete structure. Some chairs also have additional desirable features. For example, U.S. Pat. No. 5,729,949 to Hartzheim discloses a readily stackable chair with a hollow-conical body that minimizes the amount of shipping and storage space required. These chairs have support legs with apertures between them to allow concrete to flow into the hollow interior of the chair. A worker can carry many chairs at one time and place numerous chairs at a construction site without repeated trips to a storage area. U.S. Pat. No. 4,835,933 to Yung, and U.S. Pat. No. 3,693,310 to Middleton both disclose retention means or clips for use in connecting reinforcing members together. Such retention means are designed for use with intersecting or crossing bars, and provide an attractive alternative to the wires which are widely used for tying reinforcing bars together. U.S. Pat. No. 6,282,860 to Ramirez discloses a non-stackable chair for wire mesh which includes pairs of cup shaped members which engage the bars of the wire mesh and may hold the mesh via a retention means.
While the prior art chairs described above may be useful for their respective, particular objectives, the majority are generally intended for support of rebar or post-tensioning cables, which is not always effective for the support of wire mesh. Also, most prior art chairs are not able to be stacked, and therefore require an inordinate amount of space for shipping and storage. Other chairs lack retention means to reliably secure the reinforcement members.
Therefore, a need exists for a chair that is adapted to support wire mesh during pouring of a reinforced concrete structure, which not only reliably secures the wire mesh, but also is stackable for more efficient shipping and storage.